The formula to find change in entropy is given by :
[tex] Change in entropy = \frac{Q}{T} [/tex]
where Q is change in heat and T is temperature.
We are given Q = 500 joule and T = 20 degree C
Plugging these values in the formula,
[tex] Change in entropy = \frac{500}{20} [/tex]
We get change in entropy = 25 J/Celsius.
